It is known that a pneumatic tire, due to structures thereof, exhibits a cavity resonance phenomenon caused by the length of a circular tube inside the tire. Further, a pneumatic tire, regardless of the type, generates noise having cavity resonance frequency in the range of 200 Hz to 270 Hz according to a circumference length thereof, and said noise is a main cause for unpleasant vehicle-interior noise.
As described above, since air resonance in the interior of the tire is a generation factor of the vehicle-interior noise, a method for absorbing noise in the interior of a tire is effective as an improvement method. Examples of conventionally proposed methods include, as disclosed in JP200482387A (PTL 1), a technique of adhering short fibers to a tire inner peripheral surface.
Additionally, some passenger car tires adopt a tread having a pattern asymmetrical about the tire equatorial plane, from the viewpoint of abrasion resistance and the like. Such a tire has the problem that one side of the tread pattern where the negative ratio (the proportion of groove portions (portions not contacting the ground) in the tread) is higher is subjected to higher contact pressure, and thus tends to be externally damaged during driving and be more prone to puncture. This also applies to the tires with short fibers adhered to the tire inner circumferential surfaces as stated above.